考虑 Article 表中名为 ArticleCategories 的列。目标是从每行的 ArticleCategories 列中删除重复的数字 (.
ArticleCategories
------------
3193;2867;3193;
2871;2923;2923;
3278;3337;3337;
2878;2876;2878;
3720;3680;3680;
有关如何使用 SQL Server 完成此操作的任何帮助？
期望的结果
ArticleCategories
------------
3193;2867;
2871;2923;
3278;3337;
2878;2876;
3720;3680;
如果有人可以提供帮助，请提前致谢。
首先创建SplitAndRemoveDuplicates将通过分隔符分割给定字符串的函数，删除重复项并返回字符串：
CREATE FUNCTION [dbo].[SplitAndRemoveDuplicates] (@sep VARCHAR(32), @s VARCHAR(MAX))
RETURNS VARCHAR(MAX)
AS
BEGIN
DECLARE @t TABLE (val VARCHAR(MAX))
DECLARE @xml XML
SET @xml = N'<root><r>' + REPLACE(@s, @sep, '</r><r>') + '</r></root>'
INSERT INTO @t(val) SELECT r.value('.','VARCHAR(MAX)') as Item FROM @xml.nodes('//root/r') AS RECORDS(r)
;WITH cte
AS (SELECT ROW_NUMBER() OVER (PARTITION BY val ORDER BY val desc) RN
FROM @t)
DELETE FROM cte
WHERE RN > 1
RETURN (SELECT val + ';' from @t WHERE val <> '' FOR XML PATH ('') )
END
使用函数更新现有数据：
UPDATE Article
SET ArticleCategories = (SELECT dbo.[SplitAndRemoveDuplicates](';', ArticleCategories))
现在你有了一个可重用的函数。
归功于：https ://stackoverflow.com/a/314917/455770和https://stackoverflow.com/a/3822833/455770
找到了解决我的问题的方法，希望它也能帮助其他人。
CREATE FUNCTION dbo.DistinctList
(
@List VARCHAR(MAX),
@Delim CHAR
)
RETURNS
VARCHAR(MAX)
AS
BEGIN
DECLARE @ParsedList TABLE
(
Item VARCHAR(MAX)
)
DECLARE @list1 VARCHAR(MAX), @Pos INT, @rList VARCHAR(MAX)
SET @list = LTRIM(RTRIM(@list)) + @Delim
SET @pos = CHARINDEX(@delim, @list, 1)
WHILE @pos > 0
BEGIN
SET @list1 = LTRIM(RTRIM(LEFT(@list, @pos - 1)))
IF @list1 <> ''
INSERT INTO @ParsedList VALUES (CAST(@list1 AS VARCHAR(MAX)))
SET @list = SUBSTRING(@list, @pos+1, LEN(@list))
SET @pos = CHARINDEX(@delim, @list, 1)
END
SELECT @rlist = COALESCE(@rlist+',','') + item
FROM (SELECT DISTINCT Item FROM @ParsedList) t
RETURN @rlist
END
GO
SELECT dbo.DistinctList('342,34,456,34,3454,456,aa,bb,cc,aa',',') DistinctList
GO
没有光标也没有while，是本站之前问题的组合
所以答案是创建一个string Split function
CREATE FUNCTION [dbo].[StringSplit]
(
@delimited nvarchar(max),
@delimiter nvarchar(100)
) RETURNS @t TABLE
(
-- Id column can be commented out, not required for sql splitting string
id int identity(1,1), -- I use this column for numbering splitted parts
val nvarchar(max)
)
AS
BEGIN
declare @xml xml
set @xml = N'<root><r>' + replace(@delimited,@delimiter,'</r><r>') + '</r></root>'
insert into @t(val)
select
r.value('.','varchar(max)') as item
from @xml.nodes('//root/r') as records(r)
RETURN
END
查询如下所示：
declare @Article table
(
ArticleCategories varchar(100)
)
insert into @Article values
('3193;2867;3193;'),
('2871;2923;2923;'),
('3278;3337;3337;'),
('2878;2876;2878;'),
('3720;3680;3680;')
;WITH DistinctArticles AS (
SELECT DISTINCT ArticleCategories, Val
FROM @article
CROSS APPLY dbo.[StringSplit](ArticleCategories, ';')
WHERE Val <> ''
),
Concatenated AS (
SELECT
ArticleCategories,
STUFF((
SELECT '; ' + CAST([Val] AS VARCHAR(MAX))
FROM DistinctArticles
WHERE (ArticleCategories = Results.ArticleCategories)
FOR XML PATH(''),TYPE).value('(./text())[1]','VARCHAR(MAX)'),1,2,'') + ';' AS DistinctArticleCategories
FROM DistinctArticles Results
GROUP BY ArticleCategories
)
UPDATE @Article
SET ArticleCategories = Concatenated.DistinctArticleCategories
FROM @Article a
INNER JOIN Concatenated ON a.ArticleCategories = Concatenated.ArticleCategories
如果必须保留哪些行无关紧要：
DELETE FROM Article WHERE (
SELECT COUNT(*) FROM Article t WHERE
t.ArticleCategories=Article.ArticleCategories AND t.%%physloc%%<Article.%%physloc%%
)>0;
这就是我在 SQLite 中的做法，不确定我是否匹配 MS SQL Server 的语法......
尝试以下解决方案
首先创建一个UDF，如下所示
alter function dbo.SplitString2(@inputStr varchar(1000),@del varchar(5))
RETURNS varchar(max)
As
BEGIN
DECLARE @t table(col1 varchar(100))
DECLARE @table table(col1 varchar(100))
DECLARE @ret varchar(max)
Set @ret = ''
INSERT INTO @t
select @inputStr
if CHARINDEX(@del,@inputStr,1) > 0
BEGIN
;WITH CTE1 as (
select ltrim(rtrim(LEFT(col1,CHARINDEX(@del,col1,1)-1))) as col,RIGHT(col1,LEN(col1)-CHARINDEX(@del,col1,1)) as rem from @t
union all
select ltrim(rtrim(LEFT(rem,CHARINDEX(@del,rem,1)-1))) as col,RIGHT(rem,LEN(rem)-CHARINDEX(@del,rem,1))
from CTE1 c
where CHARINDEX(@del,rem,1)>0
)
INSERT INTO @table
select col from CTE1
union all
select rem from CTE1 where CHARINDEX(@del,rem,1)=0
END
ELSE
BEGIN
INSERT INTO @table
select col1 from @t
END
Set @ret = (Select distinct col1 + ';' from @table for xml path(''))
return @ret
END
然后您可以根据您的要求运行以下选择/更新查询
更新查询——这将更新您表中的记录
update ArticleCategory Set ArticleCategories = dbo.SplitString2(ArticleCategories, ';' )
选择查询——这将只选择不同的记录
Select ArticleCategories , dbo.SplitString2(ArticleCategories, ';' ) from ArticleCategory
请尝试以下解决方案，它已针对您的情况进行了全面测试，希望对您有所帮助。
DECLARE @ArticleCategories varchar(500)
DECLARE Cursor_Article CURSOR FOR
SELECT ArticleCategories from Article
OPEN Cursor_Article
FETCH NEXT FROM Cursor_Article INTO @ArticleCategories
WHILE @@FETCH_STATUS = 0
BEGIN
DECLARE @individualNum varchar(500),@ArticleCategoriesNew varchar(500) ,@ArticleCategoriesRem varchar(500)
SET @ArticleCategoriesNew='';
SET @ArticleCategoriesRem=@ArticleCategories
WHILE PATINDEX('%;%',@ArticleCategoriesRem) > 0
BEGIN
SET @individualNum = SUBSTRING(@ArticleCategoriesRem, 0, PATINDEX('%;%',@ArticleCategoriesRem))
SET @ArticleCategoriesRem = SUBSTRING(@ArticleCategoriesRem, LEN(@individualNum + ';') + 1, LEN(@ArticleCategoriesRem))
if(@ArticleCategoriesRem not like '%'+@individualNum+'%')
set @ArticleCategoriesNew=CASE WHEN ISNULL(@ArticleCategoriesNew,'')='' THEN @individualNum ELSE @ArticleCategoriesNew+';'+@individualNum+';' END
END
--If ArticleCategories is unique then leave same condition else Fetch primary key in cursor and append in Where condition of Update query
Update Article SET ArticleCategories=@ArticleCategoriesNew WHERE ArticleCategories=@ArticleCategories
FETCH NEXT FROM Cursor_Article INTO @ArticleCategories
END
CLOSE Cursor_Article;
DEALLOCATE Cursor_Article;
SELECT DISTINCT ArticleCategories FROM Article
或者
SELECT ArticleCategories
FROM Article
GROUP BY ArticleCategories
这是删除重复值
DELETE
FROM Article
WHERE ArticleCategories NOT IN
(
SELECT MAX(ArticleCategories)
FROM Article
GROUP BY ArticleCategories
)